https://btpnadzor.ru/archive/udelnaya-energiya-razrusheniya-i-gazovydelenie-iz-uglya-vybrosoopasnykh-plastov-pri-ego-razrushenii-do-chastits-opredelennogo-razmera

The study proposes a methodology for the experimental determination of the specific crushing energy of a hard coal sample. An experiment to study the process of the destruction of coal samples selected from a coal seam prone to coal and gas outbursts has been conducted. For these purposes, a device has been designed for mechanical impact on the coal sample with a load of known mass dropped from a certain height. Data on particle distribution by average diameters during the coal sample destruction have been obtained, as well as the dependence of specific crushing energy on the average-weighted radius of coal particles. Potential values of the specific energy of coal elastic compression have been calculated based on the values of measured stresses in the coal mass. The range of measured maximum stresses was 20–50 MPa. The stress-concentration factor during secondary subsidence can reach 8–9, which complies with the increase of stresses of the same depth up to 80–90 MPa that leads to the coal destruction to small-size particles: 1–60 µm or smaller. Comparing the experimental and calculated values of the specific energy of coal elastic compression has shown that these values comply with the particle size of 1–50 µm. The dependence of the generation of particles of different sizes on the type of deformation impact on a coal seam has been considered (compression across seams, compression along seams, and shear along seams). It has been established that the smallest particles are generated under shear deformations. A methodology for predicting gas emission from coal when destructed to specific size particles, developed by the authors, has been proposed. Knowing the dispersed composition of a section of coal seam, considering natural gas content and size pore distribution, the maximum volume of gas emission from a given section can be estimated, which will help develop preventive measures and thus increase the safety during the underground development of hard coal deposits.